Liquid pressure cycle having an ejector

ABSTRACT

The liquid pressure cycle having an ejector pressurizes the liquid refrigerant of the system with a positive displacement rotary pump rather than pressurizing the vapor refrigerant with a vapor compressor. This high-pressure liquid proceeds into two pressure streams. The first stream is directed to an expansion valve then on to an evaporator for space air or other medium cooling. The second stream is directed to the driving force input port of an ejector. This high-pressure input mixes with the low-pressure output from the evaporator. The result of this mixing provides for sufficient pressure enhancement to condense the combination refrigerant vapor as it passes through the condenser. The liquid flow from the condenser proceeds back to the liquid pressure pump and the cycle is repeated.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigeration system, which utilizesa positive displacement rotary liquid pump for high-pressure refrigerantgeneration along with corresponding expansion valve, evaporator, ejectorand condenser.

2. Description of the Prior Art

The vapor compression refrigeration cycle is the predominate coolingmethod for millions of residential and commercial installations. Thevapor compression cycle utilizes a vapor compressor to increase alow-pressure refrigerant gas to a high-pressure refrigerant gas. Thehigh-pressure gas then passes through an air or water-cooled condenserwhere the gas changes state into a high-pressure liquid upon the removalof heat from the high-pressure gas. This high-pressure liquid thenpasses through an expansion valve into an evaporator. During thisexpansion process, heat is absorbed in the evaporator with space air orother medium being circulated through the evaporator. The net result isthe cooling of the conditioned space or medium.

The vapor compression cycle has only been improved on the margins.Typical improvements include more efficient vapor compressor designs,larger condenser and evaporator coils, use of variable speed modulation,use of liquid centrifugal pumps for increased expansion valve efficiencyand the use of ejectors to reduce the amount of work expended by a vaporcompressor. The goal of the liquid pressure cycle is to overcome thelimited on the margin improvements of the vapor compression cycle.

SUMMARY

The liquid pressure cycle having an ejector pressurizes the liquidrefrigerant of the system with a positive displacement rotary pumprather than pressurizing the vapor refrigerant with a compressor. Thehigh-pressure liquid divides into two pressure streams. The first streamis directed to an expansion valve then on to an evaporator for space airor other medium cooling. The second stream is directed to the drivingforce input port of an ejector. This high-pressure input mixes with thelow-pressure output from the evaporator. The result of this mixingprovides for sufficient pressure enhancement to condense the combinationrefrigerant vapor as it passes through the condenser. The liquid flowfrom the condenser proceeds back to the liquid pressure pump and thecycle is repeated.

The horsepower to pressurize a liquid for a given mass flow ofrefrigerant for the liquid pressure cycle is significantly less than thehorsepower required for a vapor compression cycle of equal mass flow.

It is an object of the invention to provide a simple refrigerationsystem with significant advantages over systems in the prior art.

Additional objects and advantages of the invention are set forth, inpart in the description which follows, and in part, will be obvious fromdescription or may learned by practice of the invention. The objects andadvantages of the invention will be realized in detail by means of theinstrumentalities and combinations particularly pointed out in theappended claim.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing is incorporated in and form a part of thespecification and together with the descriptions serves to explain theprinciples of the invention in which FIG. 1 is a schematic diagram ofthe liquid pressure cycle having an ejector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It is understood that both the foregoing general description andfollowing detailed description are exemplary and explanatory only, andare not restrictive of the invention as claimed. The accompanyingdrawing which is incorporated herein for reference, and constitute partof the specifications, illustrate certain embodiments of the invention,and together with the detailed description serve to explain theprinciples of the present invention.

Reference will now be made in detail to the embodiment of therefrigeration system of the present invention. This example isillustrative only and should not be construed to limit the inventionunnecessarily.

As shown in FIG. 1 the refrigeration cycle of the present inventionbegins with increasing the pressure of a liquid refrigerant with ahigh-pressure positive displacement rotary pump 10 powered by a fixed orvariable speed motor 11.

This high-pressure liquid travels through conduit 12 and enters theexpansion valve 13 then into the evaporator 14. The expansion valve 13opens and closes depending upon the set point temperature requirementsof the evaporator 14. There are several schemes to accomplish thiscontrol function currently in use today. During this expansion process,heat is absorbed in the evaporator 14 with space air or other mediumbeing circulated through the evaporator 14.

The low-pressure gas output of the evaporator 14 proceeds throughconduit 15 to the low-pressure port 17 b of the ejector 17. Concurrentlyapproximately fifty percent of the high-pressure flow from the liquidpressure pump 10 proceeds through conduit 16 to the driving force port17 a of the ejector 17. This high-pressure liquid input decompresses andmixes with the low-pressure gas output from evaporator 14. The ejectorprocess results in sufficient pressure enhancement which is required forthe temperature conditions of condenser 19. Upon leaving ejector 17, therefrigerant flow proceeds through conduit 18 and enters condenser 19where heat is removed from the refrigerant thereby condensing into aliquid. The pressure enhancement capabilities of a typical ejector ismore fully described in an early U.S. Pat. No. 3,277,660 and mostrecently refined in U.S. Pat. No. 6,438,993. Upon leaving condenser 19,the liquid refrigerant then proceeds through conduit 20 to thehigh-pressure liquid pressure pump 10 and the cycle is repeated.

It will be apparent to those skilled in the art that variousmodifications can be made in the construction and configuration of thepresent invention without departing from the scope or spirit of theinvention. For example, the embodiment mentioned above is illustrativeand explanatory only. Various changes can be made in material as well asthe configuration of the device to engineer the specific desiredoutcome. Thus it is intended that the present invention cover themodifications and variations of the invention, provided they come withinthe scope of the appended claims and their equivalents.

1. A liquid pressure cycle comprising: a positive displacement rotaryliquid pump for high pressure generation; an expansion valve disposed atthe outlet side of the high-pressure liquid pump; an evaporator forevaporating low-pressure refrigerant after being decompressed by anexpansion valve; an ejector for mixing high-pressure and low-pressurerefrigerant streams whose combined output pressure is enhanced and sentto a condenser; a condenser for cooling and condensing refrigerantdischarged from the ejector.